Preventing corrosion



3,063,790 PREVENTING CURROSEGN Ernest L. Pollitzer, Hinsdale, Ill.,assignor to Universal Oil Products Company, Des Plaines, Ill., acorporation of Delaware No Drawing. Filed July 13, 1960, Ser. No. 42,5066 Claims. (Cl. 21-2.7)

This is a continuation-in-part of my copending application Serial No.658,778, filed March 27, 1957, now abandoned, and relates to the use ofnovel Water soluble inhibitors in preventing corrosion of metallicsurfaces upon contact with water.

Corrosion of metallic surfaces, particularly iron and steel, in contactwith fresh or salt water or various aqueous solutions, results in aSerious economical loss. There is an urgent need for, and the presentinvention provides, improved water soluble corrosion inhibitors whichwill retard and/or prevent such corrosion.

While the novel inhibitors of the present invention may be used in anysystem wherein water or aqueous solutions contact metallic surfaces, thefollowing specific examples are set forth as illustrative, but notlimiting, instances in which the inhibitors of the present invention areuseful. Storage tanks, pipe lines and the like containing petroleum oilsor other organic compounds generally contain water which causescorrosion of the metallic surfaces. For example, in storage tanks thewater settles to the bottom and causes corrosion of the internalsurfaces of the storage tank. The water soluble corrosion inhibitor ofthe present invention will dissolve in the water phase and will serve toretard and/or prevent such corrosion. Another example is in thestamping, rolling or other working of metal in which a water stream issprayed or otherwise used as a coolant. Because these operations areefiectecl at high temperature, the water fuses into or otherwise isintimately attached to the metal, and this in turn results in subsequentcorrosion. Such corrosion is avoided by incorporating the corrosioninhibitor of the present invention in the water spray. Still anotherapplication is in the salt-ice Water solutions used as refrigerants, forexample, in railroad cars, trucks, etc. When used in railroad cars, thesalt solution not only efiects corrosion of the railroad cars but alsodrips onto the rails and causes corrosion thereof. It is readily seenthat such corrosion is a serious economical problem because it requiresfrequent replacement of rails, which is expensive both in manpower andin material cost. Still other applications include boiler water, acidsolutions such as Patented Nov. 13, 1962 it is understood that thecorresponding bromo and iodo compounds may be employed. In some cases,epidihalohydrin compounds may be utilized. It is understood that thedifferent epihalohydrin compounds are not necessarily equivalent in thesame or different applications and that, as hereinbefore set forth,epichlorohydrin is preferred. In some cases, mixtures of epihalohydrincompounds and particularly of those set forth above may be employed.

Preferably the epihalohydrin compound first is reacted with anoleophilic amine. Any suitable oleophilic amine may be employed andpreferably comprises an aromatic or alkyl amine containing at least sixand still more particularly at least twelve carbon atoms and generallywill range up to about 40 carbon atoms per molecule. A preferredaromatic amine comprises dodecylaniline. Other aromatic amines includeaniline, methyl aniline, ethyl aniline, propyl aniline, butyl aniline,amyl aniline, hexyl aniline, heptyl aniline, octyl aniline, nonylaniline, decyl aniline, undecyl aniline, dodecyl aniline, tridecylaniline, tetradecyl aniline, pentadecyl aniline, hexadecyl aniline,heptadecyl aniline, octadecyl aniline, nonadecyl aniline, eicosylaniline, heneicosyl aniline, docosyl aniline, tricosyl aniline,tetracosyl aniline, pentacosyl aniline, hexacosyl aniline, heptacosylaniline, octacosyl aniline, nonacosyl aniline, triacontyl aniline,hentriacontyl aniline, dotriacontyl aniline, tritriacont-yl aniline,tetratriacontyl aniline, pentatriacontyl aniline, hexatriacontylaniline, heptatriacontyl aniline, octa-triacontyl aniline,nonatriacontyl aniline, tetracontyl aniline, etc. or mixtures thereof.In general, a long chain alkyl substituent on the aromatic nucleus ispreferred, the long chain alkyl substituent containing at least sixcarbon atoms. However, in another embodiment, two or more alkylsubstituents may be attached to the aromatic nucleus of the anilinemolecule. Illustrative preferred compounds in this class include dihexylaniline, diheptyl aniline, dioctyl aniline, dinonyl aniline, didecylaniline, diundecyl aniline, didodecyl aniline, ditridecyl aniline,ditetradecyl aniline, dipentadecyl aniline, dihexadecyl aniline,diheptadecyl aniline, dioctadecyl aniline, etc., or mixtures thereof.

Illustrative examples of alkyl amines include hexyl amine, heptyl amine,octyl amine, nonyl amine, decyl amine, undecyl amine, dodecyl amine,tridecyl amine, tetradecyl amine, pentadecyl amine, hexadecyl amine,heptadecyl amine, octadecyl amine, nonadecyl amine, eicosyl amine,heneicosyl amine, docosyl amine, tricosyl amine, tetracosyl amine,pentacosyl amine, hexacosyl amine, heptacosyl amine, octacosyl amine,nonacosyl amine, triacontyl amine, hentriacontyl amine, dotriacontylamine, tritriacontyl amine, tetratriacontyl amine,

1k ckling solutions, etc. 2 The novel corrosion inhibitor of the presentinvention pentatriacontyl amine, hexatriacontyl amine, heptatria- {jprepared by the reaction of an epihalohydrin compound with both anoleophilic amine and with a lyophilic amino compound. The term lyophilicis used in the present specifications as being synonymous withhydrophilic and these terms are used interchangeably herein. Therelatively polar amine groups serve to attract the inhibitor to themetal surface where the hydrocarbon substituent of the oleophilic aminecovers the surface and exerts a protective action by keeping watersoluble corroden-ts away from the metal. The lyophilic amino grouprenders the inhibitor compound water soluble so that it will penetratethe water layer or film covering the metallic surfaces and thereby willcover and protect -the metallic surfaces in the manner hereinbefore setforth.

Any suitable epihalohydrin compound may be utilized in preparing theinhibitor compound. Epichlorohydrin is preferred. Gther epichlorohydrincompounds include 1,2-epoxy-4-chlorobutane, 2,3-epoxy-4-chlorobutane,1,2- epoxy-S-chloropentane, 2,3-epoxy-5-chloropentane, etc. In general,the chloro derivatives are preferred, although contyl amine,octatriacontyl amine, nonatriacontyl amine, tetracontyl amine, etc.,dihexyl amine, diheptyl amine, dioctyl amine, dinonyl amine, didecylamine, diundecyl amine, didodecyl amine, ditridecyl amine, ditetradecylamine, dipentadecyl amine, dihexadecyl amine, diheptadecyl amine,dioctadecyl amine, dinonadecyl amine, dieicosyl amine, etc., or mixturesthereof. Conveniently the long chain amines are prepared from fattyacids or more particularly from mixtures of fatty acids formed asproducts or by-products. Such mixtures of amines are availablecommercially, generally at lower prices and, as another advantage of thepresent invention, the mixtures may be used without the necessity ofseparating individual amines in pure state. An example of such a mixtureis hydrogenated tallow amine which is available under various tradenames including Alamine HZGD and Armeen HTD. These products comprisemixtures predominating in alkyl amines containing 16 to 18 carbon atomsper molecule, although they contain a small amount of octadecenyl amine.Another example of such a mixture available commercially is Armeen ZHTwhich consists primarily of dioctadecyl amine and dihexadecyl amine.

A preferred class of alkyl amines for use in the present invention isN-alkyl polyamines. Preferred compounds compriseN-alkyl-1,3-diaminopropanes in which the alkyl group contains at leastsix and still more particularly at least twelve carbon atoms.Illustrative examples include N-heXyl-1,3-diaminopropane, N-heptyl1,3-diaminopropane, N-octyl-l,3-diaminopropane,N-nonyl-1,3-diaminopropane, N-decyl-1,3-diaminopropane,N-undecyl-1,3-diaminopropane, N-dodecyl-1,3-diaminopropane,N-tridecyl-1,3-diaminopropane, N-tetradecyl-1,3-diaminopropane,N-pentadecyl-1,3-diaminopropane, N-hexadecyl-l, 3-diaminopropane,N-heptadecyl-1,3-diaminopropane, N- octadecyl-l,3-diaminopropane,N-nonadecyl-l,3-diaminopropane, N-eicosyl-1,3-diaminopropane,N-heneicosyl-l, 3-diaminopropane, N-docosyl-1,3-diaminopropane,N-tricosyl-1,3-diaminopropane, N-tetracosyl-1,3-diaminopropane, etc., ormixtures thereof. As before, mixtures are available commercially andadvantageously are used for the process of the present invention. Suchmixtures include Duomeen T and Diam which compriseN-tallow-1,3-diaminopropane and predominate in alkyl groups containingfrom 16 to 18 carbon atoms each, although the mixtures contain a smallamount of alkyl groups containing 14 carbon atoms each. Another mixtureavailable commercially is N-coco-1,3-diaminopropane which contains alkylgroups predominating in 12 to 14 carbon atoms each. Still anotherexample is N-soya-l,3-diamino-propane which predominates in alkyl groupscontaining 18 carbon atoms per group, although it contains a smallamount of alkyl groups having 16 carbon atoms.

While the N-alkyl-1,3-diaminopropanes are preferred compounds of thisclass, it is understood that suitable N- alkyl ethylene diarnines,N-alkyl-l,3-diaminobutanes, N- alkyl-1,4-diaminobutanes,N-alkyl-1,3-diaminopentanes, N alkyl-1,4-diaminopentanes,N-alkyl-l,5-diaminopentanes, N-alkyl-l,3-diaminohexanes,N-alkyl-1,4-diamino hexanes, N-alkyl-1,5-diaminohexanes,N-alkyl-1,6-diaminohexanes, etc., or mixtures thereof may be employed,but not necessarily with equivalent results.

In general, it is preferred that the aliphatic amine is an alkyl amineand thus is a saturated compound which does not contain a double bond inthe chain. However, in some cases, unsaturated compounds may beemployed, provided they meet the other requirements hereinbefore setforth, although not necessarily with equivalent results. Such aminecompounds conveniently are prepared from unsaturated fatty acids and,therefore, may be available commercially at lower cost. Illustrativeexamples of such amine compounds include dodecylenic amine,didodecylenic amine, N-dodecylenic ethylene diamine,N-dodecylenic-1,3-diaminopropane, oleic amine, dioleic amine, N-oleicethylene diamine, N-oleic-1,3-diaminopropane, linoleic amine, dilinoleicamine, N-linoleic ethylene diamine, N-linoleic-1,3-diaminopropane, etc.,or mixtures thereof.

As hereinbefore set forth, the epihalohydrin compound preferably isreacted first with the oleophilic amine and then the reaction product isfurther reacted with a lyophilic amino compound, the latter also beingnamed as hydrophilic amino compound. In one embodiment, the lyophilicamine comprises an alkylene polyamine, a particularly preferred alkylenepolyamine being tetraethylene pentamine. Other alkylene polyaminesinclude triethylene tetramine, pentaethylene hexamine, etc.,tetrapropylene pentamine, pentapropylene hexamine, etc., or mixturesthereof. As hereinbefore set forth, the corrosion inhibitor of thepresent invention is water soluble, this property being achieved, inthis embodiment of the invention, through the use of an alkylenepolyamine or polyaminoalkane which is sufiiciently water soluble toimpart water solubility to the complete inhibitor molecule. Therefore,the particular lyophilic amine used must be selected with regard to theother constituents of the inhibitor so that the final inhibitor compoundis water soluble. For example, when the oleophilic amine comprises along chain amine, the lyophilic amine selected must impart sufiicientwater solubility to counter the contrary effect of the oleophilic amine.Thus, as an example, when the oleophilic amine comprises dodecyl anilineor N-tallow-l,3-diaminopropane, the lyophilic amine preferably comprisestetraethylene pentamine or the like.

In another embodiment of the invention, the lyophilic amino compound isan alkanolamine and preferably a dialkanolamine. Illustrative aminocompounds include monoethanolamine, diethanolamine, monopropanolamine,dipropanolamine, trishydroxymethylaminomethane, etc., or mixturesthereof. In still another embodiment, lyophilic amino compounds may beprepared by reacting an alkylene polyamine with a suitable hydroxycompound as, for example, by reacting one mol of tetraethylene pentaminewith one mol of polyethylene glycol chloride. In still anotherembodiment, other suitable compounds containing amino and hydroxylgroups may be employed including, for example, N-methyl-glucamine, whichis an amino derivative of glucose. As hereinbefore set forth, it isessential that the lyophilic group be sufiiciently water soluble toimpart water solubility to the final inhibitor compound. Thus, when theoleophilic amine comprises dodecyl aniline orN-tallow-l,S-diaminopropane, dietha nolamine or similar lyophilic aminocompound is employed. On the other hand, when the oleophilic aminecomprises a shorter chain amine, the use of monoethanol amine as thelyophilic amino compound will be satisfactory to impart water solubilityto the complete molecule.

The reaction of epihalohydrin compound with the oleophilic amine andwith the lyophilic amino compound may be effected in any suitablemanner. As hereinbefore set forth, generally it is preferred to reactthe epihalohydrin compound first with the oleophilic amine. In general,one mol of the oleophilic amine is reacted with one or two mols of theepihalohydrin compound. It is understood that, in some cases, an excessof amine or epihalohydrin may be supplied to the reaction zone in orderto insure complete reaction, the excess being removed subsequently inany suitable manner. While the desired quantity of amine andepihalohydrin may be supplied to the reaction zone and therein reacted,it generally is preferred to supply one reactant to the reaction zoneand then introduce the other reactant step-wise. Thus, when reactingequal mols of amine and epichlorohydrin, it is preferred to supply theoleophilic amine to the reaction zone and to add the epihalohydrincompound step-wise, with stirring. However, when reacting one mol ofamine with two mols of epichlorohydrin, it is preferred to add the aminestepwise to the epichlorohydrin. The temperature at this sta is keptbelow about 70 C. and preferably is at 60-65" in order to avoidinter-reaction of the intermediate pro uct. In one embodiment, thereaction product may be withdrawn from the reaction zone and purified asdesired before reaction with the lyophilic amine. In another embodiment,following the reaction of the oleophilic amine with the epihalohydrincompound, the lyophilic amino compound is passed into the reaction zoneand reacted therein with the first reaction product. Generally, it ispreferred to utilize a solvent and, in a preferred embodiment, solutionsof each amine and of the epihalohydrin compounds are each separatelyprepared, and these solutions then are commingled in the mannerhereinbefore set forth. Any suitable solvent may be employed, aparticularly suitable solvent comprising an alcohol including ethanol,propanol, butanol, etc., 2-propanol being particularly desirable.

The reaction is effected at any suitable temperature, which generallywill be within the range of from about 20 to about 100 C. and preferablyis within the range of from about 50 to about C., the first stagereaction generally being at the same or preferably lower temperaturethan the second stage reaction. A higher temperature range of from about30 to about 150 C. or more, and preferably of from about 50 to about 100C. is specified when the reaction is effected at superatmosphericpressure to increase the reaction velocity. Conveniently, this reactionis effected by heating an amine or amino compound solution in dilutealcohol at refluxing conditions, with stirring, gradually adding theepihalohydrin compound thereto, and continuing the heating until thereaction is completed. The other amine or amino compound solution thenis added to the reaction product and the heating continued until thesecond reaction is completed.

Either before or after removal of the reaction product from the reactionzone, the product is treated to remove halogen, generally in the form ofan inorganic halide salt as, for example, the hydrogen halide salt. Thismay be effected in any suitable manner and generally is accomplished byreacting the product with a strong inorganic base such as sodiumhydroxide, potassium hydroxide, etc., to form the corresponding metalhalide. The reaction to form the metal halide generally is effectedunder the same conditions as hereinbefore set forth. After this reactionis completed, the metal halide is removed in any suitable manner,including filtering, centrifugal separation, etc. It is understood thatthe reaction product also is heated sufiiciently to remove alcohol andwater and this may be effected either before or after the treatment toremove the inorganic halide.

While it generally is preferred to react the epihalohydrin compound withthe oleophilic amine first and then react the product with the lyophilicamine, the reverse procedure may be employed. In the latter embodiment,the lyophilic amine is reacted with the epichlorohydrin and then one ortwo mols of the reaction product are reacted further with the oleophilicamine. These reactions are effected in substantially the same manner asdescribed hereinbefore. It is understood that the temperature in thefirst stage will be controlled to prevent inter-action of theintermediate product.

The reaction products prepared in the above manner are new compositionsof matter. Depending upon the reactants and conditions employed, thereaction product generally will comprise a mixture of differentcompounds, which mixture may include polymeric compounds. Anotheradvantage to the present invention is that the mixture of compoundsprepared in the above manner may be utilized without the added expenseand time of Separating a specific compound from the mixture. Thereaction products will range from liquids to solids and, when desired,may be prepared as a solution in a suitable solvent for ease of handlingand using.

As hcreinbefore set forth, the reaction product prepared in the abovemanner is utilized as a water soluble corrosion inhibitor. It isincorporated in water, aqueous solutions or substrates containing waterin a sufficient concentration to effectively retard corrosion ofmetallic surfaces. Generally, it will be utilized in a concentration ofbelow about 1% by weight of the water, aqueous solution, or substratecontaining water, and usually in concentration within the range of fromabout 0.000 l% to about 1% and particularly from about 0.01% to about0.5% by weight thereof, although higher concentrations may be employedwhen excessive corrosion is encountered. It is understood that thecorrosion inhibitor may be used in conjunction with other additiveswhich are incorporated in the substrate for various reasons.

The following examples are introduced to illustrate further the noveltyand utility of the present invention but not with the intention ofunduly limiting the same.

Example I The corrosion inhibitor of this example was prepared by thereaction of dodecyl aniline with epichlorohydrin,

followed by reaction with diethanolamine. Specifically, a dilutesolution of dodecyl aniline in 2-propanol was prepared and was suppliedto an autoclave and heated to -90 C., with stirring. The dodecyl anilinewas utilized in an amount of 0.5 mol. One mol of epichlorohydrin,separately prepared as a solution of 2-propanol, was added gradually tothe autoclave, and the heating and mixing continued for 5 hours. 0.1 molof the resubant product then was refluxed with 0.22 mol ofdiethanolamine, separately prepared as a solution in 2-propan'ol, for 4hours. Following completion of the reaction, sodium methoxide was added,and the resultant sodium chloride was removed by filtration, followingwhich the solvent was removed by distillation. The remaining product wasa reddish brown semi-solid, which turns to a dark yellow viscous, butfree flowing, liquid at about C., and is water soluble.

The product prepared in the above manner was evaluated as a corrosioninhibitor by the following method. A 600 cc. beaker was used as thereaction vessel and 300 cc. of a 5% sodium chloride soluiton containingthe inhibitor was introduced into the beaker. A 0.5" x 3" x /s mildsteel strip Was inserted in the beaker and held in a horizontal positionwith one end resting on a glass rod. The sodium chloride solution wasstirred by a single blade stirrer revolving at 250 rpm. Air wascontinuously bubbled in at the rate of 5.6 liters per hour.

When evaluated in the above manner, a steel strip, after six hoursexposure in a brine not containing inhibitor, showed a weight loss of22-24 mg.

0.1% by weight of the corrosion inhibitor prepared in the above mannerwas incorporated in another sample of the brine and, when evaluated inthe manner described above, the loss in weight was 10.6 mg. It will benoted that the loss in weight was reduced to substantially onehalf ofthat occurring in the absence of this inhibitor.

Example 11 The corrosion inhibitor of this example was prepared by thereaction of one mol of dodecyl aniline with one mol of epichlorohydrin,followed by the reaction of the product with one mol of tetraethylenepentamine. These reactions were effected in substantially the samemanner as hereinbefore set forth; namely, dodecyl aniline dissolved in2-propanol was heated with stirring to refluxing conditions and one molof epichlorohydrin gradually added thereto. After the reaction wascompleted, one mol of tetraethylene pentamine was added gradually to thereaction zone while the heating and mixing were continued. Thereafter,sodium hydroxide was added to the mixture, with the heating and stirringbeing continued, followed by filtering to remove sodium chloride anddistillation to remove the solvent. The remaining product was a lightyellow viscous liquid, having an index of refraction 11 of 1.521, and iswater soluble.

0.01% by weight of the inhibitor prepared in the above manner wasincorporated in the brine solution and evaluated in the manner describedin Example 1. After six hours exposure, the steel strip lost 8.6 mg.heating. The visual appearance of the strip was good. On the other hand,the visual appearance of the strip exposed to the brine in the absenceof inhibitor was poor, i.e., the strip was essentially completelycovered with rust. It will be noted that 0.01% of the corrosioninhibitor served to reduce corrosion loss from 2224 mg. to 8.6 mg.

Example III Another corrosion inhibitor was prepared in substantiallythe same manner as described in Example H, except that one mol ofdodecyl aniline was added dropwise to and reacted with two mols ofepihalohydrin, and then reacted with two mols of tetraethylenepentamine. This reaction product was a yellowish orange viscous liquid,having an index of refraction 11 of 1.523, and is water soluble.

0.05% by weight of the inhibitor prepared in the above manner wasevaluated in the same manner as described in the previous examples.After six hours exposure, the steel strip appeared only lightly rustedand lost only 7.6 mg. In this case, it will be noted that the corrosionwas reduced to substantially one-third of that occurring in the absenceof the inhibitior.

Example I V The oleophilic amine used in this example isZ-ethylhexylamine. It was reacted with two mols of epichlorohydrin andthe product then was reacted with two mols of diethanolamine. The finalproduct was a bright yellow, slightly viscous liquid, having an index ofrefraction n of 1.4796 and is fluid at 45 C. and water soluble.

When incorporated in a concentration of 0.05% by weight in the brine andevaluated in the manner hereinbefore described, the steel strip aftersix hours exposure lost 8.5 mg. Here again, it will be noted that theinhibitor served to considerably reduce corrosion, in this case reducingthe loss from 22-24 mg. to 8.5 mg.

Example V The corrosion inhibitor of this example was prepared by thereaction of one mol of Z-ethylhexylamine with two mols ofepichlorohydrin and the product then was reacted with two mols oftrishydroxymethylaminomethane. The reaction was effected insubstantially the same manner as hereinbefore set forth. The finalproduct was a light yellow semi-solid which became fluid at 40-45 C. andis water soluble.

When incorporated in a concentration of 0.05 by weight in the brine andevaluated in the manner hereinbefore described, the steel strip aftersix hours exposure lost only 2.5 mg. It will be noted that thisinhibitor was extremely efiective in reducing the corrosion.

Example VI The lyophilic amino compound used in this example wasprepared by the reaction of one mol of tetraethylene pentamine with onemol of polyethylene glycol chloride 410, i.e., of average mol weight 410or containing 9-10 oxyethylene units. This reaction was eflected byrefluxing the reactants at 78 C. in ethanol solution, followed byfiltering to remove sodium chloride. The resultant tetraethylenepentamine-glycol was reacted with the reaction product of one mol ofN-tallow-1,3-diaminopropane (Duomeen T) with epichlorohydrin. The finalreaction product was a light brown viscous liquid, having an index ofrefraction n of 1.4828 and is water soluble.

0.01% by weight of the inhibitor prepared in the above manner wasincorporated in another sample of the brine and evaluated in the mannerhereinbefore described. After six hours exposure, the steel strip lostabout 11 nag. In contrast, a control sample, exposed to the brine notcontaining this inhibitor, lost about 24 mg. Here again, it will benoted that the inhibitor served to considerably reduce corrosion.

I claim as my invention:

1. The method of retarding corrosion of metal upon contact with waterwhich comprises effecting said contact in the presence of a watersoluble corrosion inhibitor comprising the reaction product of anepihalohydrin with an oleophilic amine and with a hydrophilic aminocompound.

2. The method of retarding corrosion of metal upon contact with waterwhich comprises effecting said contact in the presence of a Watersoluble corrosion inhibitor comprising the reaction product of anepihalohydrin with an oleophilic amine selected from the groupconsisting of aromatic amines and alkyl amines and with a hydrophilicamino compound.

3. The method of retarding corrosion of metal upon contact with waterwhich comprises effecting said contact in the presence of a watersoluble corrosion inhibitor comprising the reaction product ofepichlorohydrin with dodecyl aniline and with tetraethylene pentamine.

4. The method of retarding corrosion of metal upon contact with waterwhich comprises efiecting said contact in the presence of a watersoluble corrosion inhibitor comprising the reaction product'ofepichlorohydrin with dodecyl aniline and with diethanolamine.

5. The method of retarding corrosion of metal upon contact with waterwhich comprises effecting said contact in the presence of a watersoluble corrosion inhibitor comprising the reaction product ofepichlorohydrin with Z-ethylhexyl amine and with trishydroxymethylaminomethane.

6. The method of retarding corrosion of metal upon contact with waterwhich comprises effecting said contact in the presence of a watersoluble corrosion inhibitor comprising the reaction product ofepichlorohydrin with N-tallow-1,3-diaminopropane and then reacting theresultant product with the reaction product of tetraethylene pentamineand polyethylene glycol chloride.

References Cited in the file of this patent UNITED STATES PATENTS1,845,403 Eisleb Feb. 16, 1932 2,598,213 Blair May 27, 1952 2,864,775Newey Dec. 16, 1958

1. THE METHOD OF RETARDING CORROSION OF METAL UPON CONTACT WITH WATERWHICH COMPRISES EFFECTING SAID CONTACT IN THE PRESENCE OF A WATERSOLUBLE CORROSION INHIBITOR COMPRISING THE REACTION PRODUCT OF ANEPIHALOHYDRIN WITH AN OLEOPHILLIC AMINE AND WITH A HYDROPHILIC AMINOCIMPOUND.